With the rapidly expanding use of wireless telecommunications, there is a growing demand for new antenna sites. Each new antenna site has usually required the installation of a separate antenna tower. However, there is growing opposition from communities to the proliferation of these towers because these communication towers and antennas are visually polluting the landscape. Often it is very difficult (or even impossible) to obtain approvals from zoning boards, planning commissions and environmentalists to erect new antenna towers. Furthermore, the time to obtain permits (if feasible) and the time and cost to design foundations and construct these communication towers are excessive.
To satisfy this demand for antenna sites without adding more and more towers, it has been discovered that existing electric power transmission towers make ideal sites for the installation of wireless telecommunication antennae. Others have implemented modifications to existing electric power transmission towers which either involve (a) the installation of a foundation in the center and at the base of the tower to support a steel pole which is inserted inside the existing tower and the antenna array is mounted on top of this pole, or (b) mounting standoff brackets on the side of each leg of the tower, which are used to support the antenna array.
Both of these methods have shortcomings. The first method, "steel pole inserted inside an existing tower design" usually requires soil testing, and designing and pouring a concrete foundation which is used to support the vertical load of the pole and the antenna. The curing time for the concrete foundation could be 2 to 3 weeks and a few days are needed to erect the steel pole and structurally tie it to the existing tower which provides the lateral support for the steel pole and its antenna. The shortcoming of this design is not only its high cost and the excessive time it takes to design and construct, but it also requires a modification to the electric power transmission towers which have a single lightning shield wire at the top center of the tower. The steel pole which is inserted within the electric power transmission tower cannot be installed without interfering with this shield wire. Therefore, this design requires structural modification of the steel members at the tower top.
The second method of using "standoff brackets" to support the antenna does not require a foundation. However, if the antenna array is mounted on the tower legs between the electric power conductors it cannot be rotated to optimize the communication efficiency, because to do so reduces the electrical clearances between the antenna and the electric power conductors. Also, if the antenna is mounted below the electric power phase conductors on the tower this method reduces the effective height and thus the usefulness of the antenna communication system.
To overcome the shortcomings of the above designs, the inventors have developed a wireless telecommunication antenna mount which has the following advantages over the current state-of-the-art:
1. No foundation is required which reduces the cost of the antenna tower; PA1 2. No additional antenna tower or steel pole is needed to support the antenna array, which reduces the cost to install the antenna; PA1 3. The antenna mount design can be installed on any electric power transmission tower and does not interfere with the existing single or double shield wire tower designs (and does not require removing and re-attaching shield wires), because it is installed above the shield wire(s); PA1 4. The design contains a method that allows the antenna array to be rotated and aligned to improve communication efficiency without reducing electrical clearances; PA1 5. Because the design does not require a new site, the time consuming process to obtain the necessary permits for an antenna is substantially reduced; PA1 6. The design includes a unique hanger bracket, which is used to support the antenna coax cables from the antennas to the ground based equipment. These brackets are installed on the existing tower legs without field drilling the tower legs to attach same; PA1 7. The antenna mount could be installed with a helicopter and attached to the electric power transmission tower without detaching the shield wires or de-energizing the entire transmission line. The latter feature is of significant benefit, especially where antenna mounts are installed on electric power transmission towers in remote areas or in mountainous terrains where foundations would be impractical to construct and or where it would be difficult to obtain a line shut-down to install the antenna mount; PA1 8. The weight of this antenna mount is significantly less than the "steel pole inserted inside an existing tower" design, and the weight is independent of the height of the electric power transmission tower; and PA1 9. The height of the antenna can be increased above the height of the tower by just extending the length of the antenna mounting members.
In accordance with this invention, a wireless telecommunication antenna mount is supported by the upper portion of an electric power transmission tower in a position above the tower and thus readily enables use with single and double shield wire tower designs. The antenna mount comprises a platform adapted to carry a plurality of antennas. The platform is mounted on a pedestal, and the pedestal in turn is mounted on the transmission tower.
Preferably, the antenna platform is adjustably mounted on the pedestal so that it may be angularly adjusted as desired. In the preferred embodiment about to be described, the means for angularly adjusting the platform comprises two circular plates which may be relatively rotated to the desired angular position and then secured together. This rotation or angular positioning can be accomplished either manually, or remotely by using a mechanized system to rotate the platform without interfering with the energized electric power transmission line.
One object of this invention is to provide a wireless telecommunication antenna mount having the foregoing features and capabilities.
Another object is to provide a wireless telecommunication antenna mount which is constructed of a relatively few simple parts, is rugged and durable in use, and is capable of being easily and inexpensively manufactured, assembled and adjusted.